Photographic couplers which release a development inhibitor in a controlled manner are described in U.S. Pat. Nos. 4,248,962 and 4,409,323, inter alia. These couplers comprise a coupler moiety which has a timing group joined in its coupling position. A development inhibitor is attached to the timing group and is released from it after the bond between the timing group and the coupler is cleaved as a result of reaction between the coupler and oxidized color developing agent. Mechanisms by which such release of the development inhibitor from the timing group can occur include an intermolecular nucleophilic displacement reaction, an electron transfer reaction, and a hydrolysis reaction. Development inhibitors also can be released, as a function of development, from timing groups which are released from compounds which are not couplers such as the hydrazides of U.S. Pat. No. 4,684,604 and the hydroquinones of European Patent Application No. 0,167,168.
One of the advantageous effects obtained as a result of release of a development inhibitor, either directly from a coupler or other carrier moiety, or through a timing group as described above, is an improvement in photographic performance, such as an improvement in the sharpness of the image formed.
Also known are cyan dye-forming image couplers that contain a ureido group in the 2-position.
Lau, U.S. Pat. No. 4,333,999 issued Jun. 8, 1982, describes cyan dye-forming couplers containing p-cyanophenylureido substituents in the 2-position of the coupler. These couplers are described as yielding dyes having desirable hues and good stability properties.
U.S. Pat. Nos. 4,777,616 and 4,849,328 describe couplers which improve upon those described in the '999 patent by modifying the 5-position substituent. The '999, '616, and '328 patents suggest the use of the cyan couplers therein described in combination with DIR couplers, but do not specifically suggest that they be used with couplers of the type described in the '962 or '323 patents.
U.S. Pat. Nos. 4,434,225 and 4,609,619 describe phenolic cyan dye-forming couplers containing a ureido group in the 2-position. Use of one of these couplers with a DIR coupler is mentioned in these patents. However, they do not describe any particular combination of phenolic coupler and DIR coupler nor the particular advantage deriving from the selection of the present invention.
It would be desirable to provide color photographic materials which have improved performance.